One of the most well-known Muslims in the United States appears to have joined the rising chorus of criticism of U.S. Republican presidential candidate Donald Trump over his proposal to ban Muslims from entering the United States.

In a short statement issued Wednesday titled "Presidential Candidates Proposing to Ban Muslim Immigration to the United States," former heavyweight boxing champion Muhammad Ali urged his fellow Muslims to push back against "those who use Islam to advance their own personal agenda."

Trump has been under fire since unveiling his proposal earlier this week in a written statement and a campaign rally in South Carolina, in response to a shooting rampage at a government center in San Bernardino, California that left 14 people dead. The attack was carried out by a husband-and-wife Muslim couple investigators say had been "radicalized."

Although he didn't mention the leading Republican candidate by name, the 73-year-old Ali said political leaders who have openly denounced his religion "have alienated many from learning about Islam. True Muslims know or should know that it goes against our religion to try and force Islam on anybody."

Originally born Cassius Clay in 1942, Ali joined the Nation of Islam in 1964 and changed his name shortly after winning the first of his three heavyweight titles. He was stripped of his title after he was convicted on draft evasion charges for refusing to be drafted in the U.S. military during the Vietnam War. His conviction was later overturned by the U.S. Supreme Court.

"Speaking as someone who has never been accused of political correctness," he wrote, "I believe that our political leaders should use their position to bring understanding about the religion of Islam and clarify that these misguided murderers have perverted people's views on what Islam really is."

Ali, who has since converted to Sunni Islam, also lashed out against the recent ISIL-directed or inspired terrorist attacks, saying "there is nothing Islamic about killing innocent people in Paris, San Bernardino, or anywhere else in the world. True Muslims know that the ruthless violence of so called Islamic Jihadists goes against the very tenets of our religion."

Trump's proposal came a day after a nationally televised speech by President Barack Obama in which he urged Americans not to turn against Muslims in the wake of the terrorist attacks. The president defended Muslim Americans as "our friends and our neighbors, our co-workers, our sports heroes."

The next day, Trump went on Twitter and implied there is no such thing as a Muslim sports hero -- apparently forgetting that he had appeared in public numerous times with Ali, a fact revealed by several photos posted on the Internet of the two men together.

Virulent statements against Muslims are nothing new for Trump, who has called on the government to monitor mosques, and has refused to rule out his earlier proposal to enter the names of Muslims in America into a database.

White House spokesman Josh Earnest Tuesday called Trump's rhetoric "offensive and toxic," saying his plan "disqualifies him from serving as president" because he would be violating the U.S. Constitution if he implemented it, should he win the country's 2016 presidential contest.

Trump's political opponents have also condemned the bombastic billionaire's remarks, with former Florida Governor Jeb Bush calling him "unhinged" and South Carolina Senator Lindsey Graham accusing him of helping ISIL to recruit more fighters.